The invention relates to carbon black, a method for the production of carbon black or other flame aerosols, and a device for carrying out said method.
By means of the method according to the invention, it is intended to produce carbon black in the form of aerosols having reproducible and adjustable properties. Such properties are the carbon black concentration and the particle size distribution, the agglomeration state and the chemical composition. Such aerosols are required in order to test, for example, filters, electrostatic separators or catalysts with regard to the separation of carbon black. Furthermore, the aerosols thus obtained can be separated in order to produce, for example, pigments or fillers.
The process is also suitable for producing other aerosols producible in flames, such as, for example, SiO2 or TiO2 having particular properties.
The literature has to date disclosed 2 methods for producing test aerosols from carbon black.
In the arc method (C. Helsper, W. Molter, G. Wenninger: Investigation of a New Aerosol Generator for the Production of Carbon Aggregate Particles. Atmospheric Environment, Vol. 27A (1993), pp 1271-1275), an arc is ignited at short time intervals between two carbon electrodes which are present in argon gas. A small amount of the electrode material is vaporized and condenses in the argon stream to form fine carbon black particles which are discharged with the argon stream. The method has two disadvantages: firstly, the carbon black produced consists exclusively of carbon whereas real carbon black always contain proportions of hydrocarbons and oxygen which influence the properties to a very great extent. Secondly, only very small amounts of aerosol which are generally not sufficient for the abovementioned applications can be produced by this method.
In the quench gas method (L. Jing: Neuer Russgenerator für Verbrennungsruβteilchen zur Kalibrierung von Partikelmessgeräten [New carbon black generator for combustion carbon black particles for the calibration of particle measurement devices]. OFMETInfo Vol. 7 (2000), no. 2, pp 8-12), a diffusion flame is cooled by supplying a large amount of quench gas (e.g. nitrogen) and is extinguished. In this method, it is true that carbon blacks having a realistic chemical composition are produced. The very high consumption of quench gas, which gives rise to considerable costs, is problematic. This type of carbon black aerosol generator has therefore also been realized to date only for very small flow rates.